Advancing Cardiac Arrest Care, SPEAR; Roadside to Resus

So hi and welcome back to the Recissoring Podcast. I'm Simon Lang. And I'm James Jates. And yes, that does mean the third member of the gang is missing. He's off apparently creating an extrication course, which seems like a reasonable excuse, but sadly he won't be here to join us for this episode, will he? He won't, no, but you're right. He has got a reasonable excuse. I mean, if he's actually indeed doing that, maybe he's sunning himself on a beach somewhere. We think he's working, but we have replaced him though with two outstanding clinicians that we're going to hear from him in a bit, so I don't feel too bad that he's taking this month off. No, and this is our last roadside to recess before our summer break, but it is an absolute belter. I'm sure you can be listening to it several times on those sun lounges when you get a chance to go on holiday. So before we get into it, a huge thanks to Zoll Medical Corporation for collaborating with us on the podcast and making this all free open access and available to you in their pursuits of excellent patient care. And we also look forward to seeing a load of you in London for a live roadside to recess in October. So without further ado, let's crack in to the episode. Okay, well, we've said this already, but this really is a pretty special episode because if you're involved in cardiac arrest management or care of critically unwell patients either in the pre-hospital arena or in hospital, then there's some groundbreaking practice we'll be discussing with the two founders of the spearcourse on this episode. Yeah, and I cannot wait to hear from them, but just before we get into that, let's have a little think about what we're going to be covering. So ultimately, we're going to be navigating through to the delivery of endovascular resuscitation, both in the pre-hospital and in hospital settings, building on the fundamentals of care and logistics, which enable the really complex delivery of this intervention in those settings. So to do that, we're going to be covering blood pressure monitoring, both invasive and non-invasive. And that's in both the critically unwell patients and in those with cardiac arrests. And we'll talk about the evidence that exists and the cohort of patients that we should be targeting for invasive blood pressure monitoring. We'll have a think about how systems can deliver complex medical interventions in unpredictable circumstances and environments and the role that we all have to play in that. We'll think about balancing the benefits of interventions and the time required and the workflow that's involved in ensuring that those interventions are delivered in a timely fashion. We're going to talk about reboa for medical cardiac arrest, the theory and the upcoming Erika Troyle. And there's also bits in there about improving recognition of risk, the spearcourse and how to prepare services and departments for upcoming advances in resuscitation. Absolutely, this is a jam-packed episode with some really useful stuff. And fortunately, to deliver that, we get a lot of help from people who know exactly what they're talking about. So first, we'll hear for John Barrett, who's a lieutenant colonel in the British Army, an emergency medicine and fem consultant at University Hospitals of the North Midlands, the clinical lead for research and clinical innovation at Yorkshire Air Ambulance, a merit consultant in the West Midlands Ambulance Service and a senior lecturer at the academic department of military emergency medicine. And joining him is Paul Rees, a surging commander in the Royal Navy, a consultant at East Angleon Air Ambulance and Bart's Heart Centre, lead for resuscitation at Bart's Health NHS Trust, reedering cardiology and resuscitation at the University of St Andrews and Queen Mary's University London and the defence lead for endovascular resuscitation. And they are both, as we've said, the founders of the Spearcourse. Oh, well, I mean, I was pretty proud of my 50-meter swing badge until I got home, and that's best. It's now been blown out of the water. But before we crack into this episode, I think there's just a couple of things to clarify, because there's an awful lot of acronyms that fly around at various points. And so I think two key ones that we just need to cover off. So we'll be mentioning ECMO, so that is specifically VA ECMO in this situation. Now, clearly, this is a pretty advanced intervention and technique, and it provides a form of temporary mechanical circulation and support, whilst also simultaneously providing gas exchange. Forming a bit of a bridge, I guess, in resuscitation when there's insufficient cardiac output, which can buy time whilst the cause of the medical arrest is identified and treated. We're also going to talk about Reboa, that's resuscitative endovascular balloon occlusion of the Aorta, you can see why it's called Reboa. And that basically is inserting a catheter into the Aorta, I say, basically, it's not really very basic, but insert a catheter into the Aorta via the femoral artery, and then you get it up to the right spot, inflate that balloon in the Aorta to prevent distal blood flow. And the guys on the podcast are going to explain all about why that's important, but hopefully that just gives you an understanding of what Reboa is, and we have covered it before in the context of trauma, but this time we're talking about it here, clearly in a bit of a different light. So let's hear what the guys had to say when they caught up with Simon. So a massive thanks to both of you. We've talked in the introduction about spear, and we'll be talking about it a lot in the episode. Do you mind just starting off by talking about what spear actually is? I'm happy to start then, so spear essentially is our way of approaching out-of-hospital cardiac arrest management. I think we realized a while ago that we weren't really taking full advantage of all of the potential physiological variables that you can understand during cardiac arrest, and by using ultrasound guided femoral access, actually able to get a lot more information about our quality of resuscitation, potentially target our therapies during resuscitation, and also it's a gateway to being able to do more advanced end-of-uscular interventions. For me, it evolved out of, initially, when we started this process, we were already training the military at deployed operational damage control, surgery and resuscitation teams in how to do Reboa, and as part of that, we were training femoral access. We realized quite early on that we didn't really train femoral access very early on, if you remember John, there was a slide that said one gain eighth inch femoral access to put device in. So we then decided we needed to have some elements of training and some task training around that, and then when we looked at what we were doing in the air ambulance and pre-hospital context, we realized we go to a large volume of cardiac arrest, it's a large part of our work, and for me, being able to deliver either a boa or echo other interventions later on, required to develop a group of people who could reliably deliver safe ultrasound guided femoral access. So that's probably where the, that and the blend of stuff that we learned from our Swedish colleagues on the EVTM program became spears, especially as percutaneous endobascular aortic resuscitation. There's some discussion, isn't there, John, about which letters exactly stand for what, but it's not all about the acronym, but it was the whole aim was to generate a group of people who could safely and reliably get ultrasound guided femoral access. And as we started doing that, we started getting insights into cardiac arrest physiology that really hadn't been there since about 20 years ago in animal and human studies. So, so that was the evolution of the process really. I think it's also worth adding as well that our colleagues in the ambulance service are continuously doing a really amazing job of resuscitating patients pre-hospitaly, as Hems teams had often arrive fairly late down the line, and it was a feeling that there must be more that we can deliver here. We were doing ultrasound during cardiac arrest, but a lot of the time that was helping to decide around decision making around futility, rather than necessary targeting interventions, and actually with the ability to do this safely, then you can actually gain a lot more information and actually contribute to the management of cardiac arrest, which I say is in the majority of cases being expertly done by our fellow pre-hospital colleagues. In terms of talking about what Hems and pre-hospital teams bring to cardiac arrest, there are a few papers on there suggesting that it doesn't improve outcomes, and that's one of the reasons we sat down and I thought, well, what are we actually bringing to the scene? Because as you say, John, an ultrasound showing emotion as heart isn't really a valuable contribution. We can all practice the patient life extinct at the end of resuscitation without ultrasound images confirming that. So what else can we bring that will help us augment resuscitation? And that's again why this evolved as part of that process. Brilliant. Well, I was lucky enough to come on the course with both of you a couple of years ago, and it was fantastic, and I think it's fair to say from that point, things have evolved quite a lot, both in terms of research that's been put out there, a lot of which you both have been involved in, and also where Spear has led to, and we'll come back to those topics of Roboa a bit later. I think what was really interesting is it gave me an idea of how services could move on with things which weren't necessarily going to end up with medical Roboa, but gave us an option to move towards that if that's something that comes out in the future as an excellence of standards of practice. But it really relied, didn't it, upon that access, that arterial access and being able to get that intra arterial blood pressure monitoring, and there's some great papers that have come out on that. Do you mind if we start off there? So could you talk a little bit about the research that's come out about values of non-invasive versus invasive blood pressure monitoring, and what advantages you've seen with the invasive approach? Absolutely, I'm happy to start with that in terms of, as an organisation at East Angling Air Ambulance, we were using in invasive blood pressure monitoring for a long period, predominantly for monitoring patients that were undergoing pre-hospital emergency anesthesia and predominantly those with neuro trauma. And that's an accepted standard in hospital. So, or if essentially DIM was projecting that pre-hospital, but what would sort of recognize this, that there is a discrepancy in a lot of these cases between the non-invasive blood pressure and the invasive blood pressure, but we didn't have any strong data to particularly support that. Our colleagues at Thames Valley, Air Ambulance have recently published an excellent paper that has essentially matched the non-invasive blood pressure data with the invasive blood pressure data. And they found some really interesting findings. It corresponds with what I think we were seeing, but they just documented it really, really well and evidence to it. And there's a couple of really great diagrams in the paper that demonstrate that really clearly. I think the most startling thing for me, in the context of invasive blood pressure, not necessarily within out of hospital cardiac arrest, but in patients that, in particular, those with neuro trauma is that the non-invasive blood pressure will typically underestimate your blood pressure when you're in a state of hypertension and overestimate your blood pressure, particularly the systolic blood pressure when you're in a state of hypertension. So, absolutely the worst possible combination. And I think until these papers are published, although it's only just observational data, it's really, really valuable in terms of demonstrating the benefit and the potential discrepancy. We've managed to do something similar with data recorded during cardiac arrest, but that's really quite challenging. I think Paul might be able to speak more about it, but until we've had the program established of being able to consistently deliver the femoral arterial access, then we weren't really able to obtain the observational data, but we now do have that. And we're able to give some specific targets to aim for intra-arrest as well. - Yeah, so it's interesting that you've come to that point, John. So, as far back as 2014 in each replay, they were using a lot of arterial pressure monitoring, what they thought, you know, traumatic brain injury like you say. And actually now, as you say, standard of care, it would be very unusual for a critically unstable trauma patient to just crack on, get a pre-ospital anesthesia, particularly as far as the three-person team without getting an arterial eye upfront. So, that is very much standard of care in our service. And I'm not sure, you know, I don't think I feel comfortable necessarily delivering that without that being available as part of the playlist of things that you can deliver. Sometimes it's not achievable, sometimes you do have to just crack on, but actually for our service, we've evolved to a position that everybody's comfortable familiar with flushing through arterial lines, zeroing pressure traces and managing invasive critical care pressure monitoring. And I think that was the starting point for us, wasn't it? It's interesting also what you say, non-invasive versus invasive. Things are actually slightly worse than that, aren't they? We know that also radial arterial pressure differs quite significantly from central aortic bud pressure. So, the situation is often a bit different when you measure a radial blood pressure, and you get to see past coronary catheters, resultant the auto, it's often 10 or 20 millimeter mercury less in the central circulation. So, we might even be falsely reassured in the settings of critical hypotension and cardiac arrest by what's going on in the radial artery. So, that was just all I was going to add to that. And then as we started analyzing our cardiac arrest data, and we looked back at the historical animal and some small human data sets, we then realized, well, what did wonder? Is this idea of coronary perfusion threshold a thing? Does it translate into, and we looked through our entire data set, thousands of patients that in base of arterial pressure monitoring. Interestingly, about 50% of those in our paper, which I'm sure you're going to come and talk about, were after we introduced the SPIR concept. So, half and half, half a radial, half a femoral, so half of them are more recent. And we noticed there was very much a pattern emerging whereby you could identify aortic and, as I was talking about pressure, it was going to be associated with survival. - So, that's going to lead really nicely into one of the papers that we've covered quite recently, which talks about blood pressure thresholds and risk and the association and perhaps what difference that might make to our practice. But Paul, you gave a pretty amazing coronary physiology tool at the beginning of the SPIR program. Do you mind, I mean, this is no great task at all. Do you mind just condensing that into a couple of minutes for the salient points from that? - Yeah, that sounds like a challenge here. So, what we need to think about when resuscitating people, and there's John often points out, there's often a light bulb moment with people when they think about what they're doing during resuscitation. We're all very busy trying to do algorithm compliant resuscitation. But what is going to make the heart restart again? To make those myocytes beat and contract, you absolutely have to be delivering oxygen to them. So, the blood has to be coming from somewhere. So, during SPIR, you need forward flow of blood down your coronary arteries. And the thing that pushes blood down the coronary arteries is pressure and that pressure is initiated and theotic route to aortic blood pressure is absolutely key. We know in life, when we're wandering around, most of our coronary perfusion, so blood flowing through the myocardium comes in dastily. And during SPIR, it's even worse, because actually, every time you compress the heart, you don't just get no forward flow. Your heart actually empties itself and you get retrograde flow and they alter from the coronary arteries. The heart empties itself, basically, the wrong way. We know that's also true in critically hypertensive trauma patients. So, things are really bad during SPIR. The only thing that's going to make you get and sustain risk. So, if you're on for a factory VF, you get a couple of shops, you get risk for a bit. Unless you've got forward flow down your coronary arteries, you're going to very rapidly end up at a much finer VF or PAA sisterly and then just be dead. So, you need sustained forward coronary flow, which is driven by aortic diastolic blood pressure to get and then sustain risk. Job done. (laughs) - Do you mind then talking about the paper that then talked about what's those significant levels of diastolic blood pressure and what the associations teased out to show? - Yeah, I'm happy to try and take that one on. So, for a while, we'd sort of had an idea in our mind about what the diastolic blood pressure threshold might be. And this is derived from understanding what the coronary perfusion pressure threshold is. So, there's good published data. It's not particularly new. It's been around since sort of 1980s, suggesting that you need a coronary perfusion pressure. So, your aortic diastolic pressure and you're left ventricular end diastolic pressure or more commonly measured the right atrial pressure 'cause it's actually achievable in patients on a critical care unit that have already got arterial lines and central venous castors and that information's obviously available. And a coronary perfusion pressure of 15 is typically what's quoted in the literature as being a coronary perfusion pressure that may give you an opportunity to achieve risk. A coronary perfusion pressure grade 715 doesn't absolutely guarantee that you'll achieve risk, but if you don't get your coronary perfusion pressure above 15, you absolutely won't achieve risk, if that makes sense. So, we've got that information, but actually that's not particularly useful to us pre-hospitalia, where the only realistic invasive blood pressure monitoring that we can get is arterial blood pressure monitoring. So, what we needed to do is work out what the diastolic blood pressure threshold which is what we could measure, that should be. And over the course of a series of over 80 patients that received invasive blood pressure monitoring, a combination of those radial and femoral reflective of the fact that the femoral option has added later into our service, we were able to identify an optimal diastolic blood pressure threshold of 35 million use of mercury, which was likely to correspond with a coronary perfusion pressure grade 15 and positively associated with a return of spontaneous circulation. And essentially, the higher and higher you can drive the diastolic blood pressure, the more likely you are to achieve return of spontaneous circulation. But what's really great is that now we've got a figure that we can look at on our monitor, and that we know if we can achieve that diastolic blood pressure, we're doing something right. It's also helpful in a way to know that if we're not managing despite all best efforts to improve that, probably also a reasonable marker that this resuscitation is probably futile. And it's not uncommon to see extremely high systolic blood pressure, so you actually are achieving perfusion to the brain and the other end organs that actually diastolic remains in the low teens, 15 or so. And sadly, I think all of us would recognize that is futile. - Okay, so we've got to a point where we've got invasive blood pressure monitoring ongoing. We've got a diastolic, which we now know might be giving us a feel towards where that cardiac arrest is going. In a similar way, I guess, to how we look at end tidal and we start to prognosticate a little bit off that. Is there a way, because we've said this in an association, is there a way that practice is then changed during those cardiac arrests to try and drive that diastolic blood pressure up? We may be at a point in which we can't talk about that because things are clearly evolving at quite a rapid rate in the research and the experience that you're building. Where are we with that at the moment? - So I think it's fair to say that we should be doing what we can to augment the resuscitation in terms of the getting optimal chronic perfusion during the resuscitation. So what things can we practically do? So we get our lines in, our pressure is not where we want it to be, what can we actually do? We can make sure we're getting effective CPR, because actually quite often a bit of rescue of fatigue is crept in at that point. Quite often, mechanical CPR has been employed as well, and that's not necessarily the free lunch that we think it should be. So a Lucas device or similar gets deployed and often moves subtly during the resuscitation or often might not have been optimally deployed in the first place. So when you get your lines in and you see your little red line wiggling up and down at 30 out of 10, that might well draw your attention to the efficacy of the CPR that's being delivered. So you could reposition or adjust the, I say, Lucas, because in our service, that's what it most commonly is. And in occasional cases, I think, well, actually, this isn't delivering compressions anywhere near in the right spot, removing it completely and going back to manual CPR. At a case last week, we had an emergency medical technician with us, so non-parametic doing chest compressions, the lines are in, and actually in the debrief artistry, he said, well, actually, it was really easy for me to target compressions, because I was looking at the red line going up and down, and aiming my compressions to optimize for a few, Now he's had no training in coronary perfusion pressures, in basic pressure monitoring, but it was really intuitive to him to very subtly change the positional rate of compression to optimize the pressure on the monitor. Now chest compression positions, we've all seen a million clips on social media of transosophageal echoes, and left ventricle outflow trap compressions, so if you're pressing in the wrong place, you will not generate forward flow, and again unless you're measuring the pressure, you won't know that you've not got forward flow. Now you may have also had some other vascular disaster that means you can't ever get forward flow, but seeing inadequate pressures might make you optimize your test compression position. I would caveat that slightly in that, again, moving all around the chest isn't a free lunch, and we know from some catavaric work that the more you do off-center CPR, the higher your chance of getting a flail. Now, survival cardiac arrest, have your flail fixed, versus not survival cardiac arrest, there was a trade off there, but it's not an absolutely guaranteed winner, particularly in older, more frail patients to press off-center. What other things can we do? We can think about altering our pharmacology during the cessation. We often only have two pharmacology-active drugs available with us in pre-ospital care in the UK, but giving one of those slightly differently, and we can talk about that in a minute, and the other thing might be choosing mechanical device to augment after flow, so to increase your magic root pressure, or the ultimate treatment I suppose, the way to make the heart restart, again, is support three and a half to four leads to minute of oxygenated blood back up the altar and down the coronary arteries, and then it will sort itself out if it's going to, and start beating. But, unless you know what's going on during CPR, all those things are off the table, so that's why we thought this was an important starting point. Great, and I think when we've talked before the episode, this is absolutely built on the fundamentals, isn't it, of the excellent care that's already ongoing, really aware that this is a small proportion of cases that we're trialing this in, and that to be able to get to the point of even looking at this, the fundamentals, and the advanced life support algorithms that people are following are extremely important, isn't it, and we're not detracting from that at all, this is about building on those amazing foundations to make this possible, isn't it? Yeah, thanks for reminding me when I, when I've sat in, had the time to actually think about the algorithm as when I was deployed in the jungle in an access to Wi-Fi or any sort of form of distractions, it's amazing what that allows you to be able to do, but the key thing for me was to have included in the algorithm, as well as all the fancy stuff like doing ultrasound guide, femoral access, was to make sure that first of all, we were including patients that already had high quality CPR ongoing, and for me the easiest way to do that, and we call this the rapid assessment phase, was to, it's something anyone can do during a cardiac arrest, is feel for pulsatility during chest compressions, and where that's radial sort of now tends to use the femoral pulsatility, because that tends to be where we're going to work thereafter. If you're not generating some form of pulse with your chest compressions and something's wrong, either chest compressions are happening in the wrong place, or the underlying cause is something that's so catastrophic that you're not able to actually generate any forward flow. If you can feel a pulse either break your femoral, even potentially radial, or see a pulsatile saturates, that's not an absolute no-go in cardiac arrest, chest compressions are good enough. Sometimes if the sat's pro has been left on, you'll actually see that it's still pulsatile. That's a suggestion that you are generating ejection, but that's only telling you half the story, and it's only telling you about the systolic blood pressure side of the equation, and obviously, as Paul's just said, the diastolic bit is important, and that then comes on when we've got the invasive blood pressure monitoring. But most important thing for me was that rapid assessment phase needed to happen to make sure that all of the bits of high quality CPR, ALS are in place before we even start to move on to the more invasive side of things. But something we've also learned is that you often need to be a bit of scene management, and expectation management at that point, don't you? Because you're going to be carrying on a resuscitation, you're going to be deploying equipment that people haven't seen before, you're going to be using techniques that people haven't seen before, sterility, you're going to have to have a conversation about what's going to happen next. So we've learned that quite rapidly, haven't we? But it's very important to have a bit of a bit of passive sorted out, so you really explain to everybody in the room on the same page, get all the information you need to know about the patient, and explain that a load of stuff that they've maybe not seen before is now going to happen. That's going to help us guide our resuscitation, and don't forget, these resuscitations are quite evolved by the time we arrive, aren't they? Particularly in HEMS services, there's a lot of people there, and probably a sensation of, you know, what the direction the categorist is going, and it starts to creep in. So if you think it's viable, often we need to do a bit of, you know, reset the scene a little bit, and particularly, as I'm sure comes talk about later with the reboa cases, and I'm sure with ECPR services, there's a lot of immediate education that needs to happen about what's going to happen next. I think it's not unreasonable to set a couple of thresholds, almost a buy-in, you need to be achieving this in order to go on to the next stage, and we used N tidal CA2 as our way of doing that. So N tidal CA2 had to be greater than or equal to 2 in order to be a candidate to go on to the further, more invasive therapies, and also there's probably something about rhythm there. Realistically, this is something for PEA, or BFRS, really, rather than racist league. You've mentioned so many bits already that I want to just ask a little bit more about so I think during that poll, you were talking about drugs, you were talking about ECPR, and then you were referring to reboa in medical causes of arrest. Could we go back a little bit to the drugs, so you're saying that there's two available to us, and clearly there's very well-defined algorithms for how drugs should be administered during arrest, but what sort of things were you were looting to, maybe as future practice or ideas? Yeah, so the first question is, I'll be using the right drug at all, so doing restocitation we're really using adrenaline to generate afterloads, so we're not trying to stimulate the heart to beat, we'll make it beat more rapidly, we're really using it for alpha agonist effects to increase afterloads, to increase vasoconstriction essentially, to increase your air to diastolic blood pressure to, again, push more blood down the coronaries. So do we have any better drugs in our critical care or momentarium that we could use to increase afterload? If you're in an intensive care unit today, and someone says we need to increase our afterload or drug you're going to reach for, we know that that's probably going to be noradrenaline, are there cardiac arrest studies using noradrenaline? Yes, there are actually prehospital and in fact in boluses, which is almost eye-watering, but are we using the right drug as the first question, and we may well not be. Now adrenaline isn't as bad as I've made it out to be, and what we've discovered through some of our roboa cases, I thought we were definitely going to need afterloads to support them at the end of their very tricky resuscitation, but actually the patients offer quite bradacardic, a bit of rate increases in the bad thing at all, so I'm not a complete down on adrenaline, but if we're trying to optimize afterload and increase coronary perfusion, then maybe a different drug or different delivery method would be the right thing. So instead of adrenaline, should it be a more strong alpha agonist, we often carry metereminol in our packs as well, really for those sort of post-RSI wobbles really, so could we give that to augment afterload potentially? Should we be giving adrenaline as a massive bolus? Now, John and I was talking about this extensively, as a slide, I think that you delivered at the Parasectomy Arrest you, of course, recently, was that you also, as someone else, as I can't remember, but in cardiac arrest, the dose when you're working out is three mics per kilo, essentially, as a huge bolus, and then we walk away and give them no further drug from the few minutes, then give a bit more when we remember to. Now in no other critical care setting, do we give vaginactive amines as a bolus in an unmonetored patient and then leave it for a few minutes and then squirt some more, and it just doesn't happen in any other setting, so why would we do it in the, by definition, sickest patients in our cohort? I don't really know. So is there another way we could deliver it? Well, we carry in our platforms in East Anglia, one or two brawn or others are available, but syringe pumps on every platform, so do we have the capacity to give it as an infusion? And during our early iterations of our spear algorithm, absolutely, it was there as an infusion. So even a mic per kilo per minute really is eye-wateringly high, but it's still less than we were giving anyway, give it at a mic per kilo per minute, and see what your rate is also, but pressure is, and then augment the rate as necessary. Is there precedent for this happening across the world? There are absolutely is. In the US, there are some centres that do this routinely, and in fact have an algorithm which targets air to target pressure based on the infusion and suggests adding invasive pressure as an additional press or agent, if you're unable to get to target. So coming back to the original question is, are there things pharmacologically we could be doing differently? Yes. So maybe a different drug, maybe a different mode of delivery, and I think probably infusion is where the clever money is, and if you look at the most recent draft ill-core guidelines, it does suggest what we should be doing in a critical care patient. So on intensive care, your patient arrests next to you, you didn't switch the adrenaline off and say, "Wang, we're not going to give any more, we're just going to give it by massive boluses," you continue an infusion, and it suggests what you should do with infusion rates, and it suggests that you should target an aerotic diastobic blood pressure. And also the most recent iteration of the pediatric substation guidelines do contain elements of aerotic diastolic blood pressure as a target. So that's a very long-winded answer to a very succinct and careful question. Now that's really useful, and I think when I'm listening to you thoughts about all of this, this is a trade-off, isn't it, between precision of delivery in the most aspirated operation or way, versus, again, the fundamentals of what can be delivered without the extra resources at a card-ecal rest, whether that be in hospital or pre-hospital, but without aiming for this aspirational level of care, then we'll never be able to draw up the fundamentals as well. So it's, you know, somebody has to be at the leading edge of a driving practice. So it's really great to hear this. Also, the other thing I'd say, Simon, is, you know, we need to also look around the world at what other people are doing, so I was fortunate to spend a day with Denise Miranda from the on-scene trial, predominantly to look at how they're delivering the amazing study that's just finished over there in pre-hospital ECPR, but it was really interesting seeing on every ambulance in the Netherlands they have an infusion pump. For their system, that's routine because it's there and available on every single ALS ambulance. So I think what we are at the moment is sometimes the guidelines are they're supporting everybody. Everybody can deliver adrenaline, boatless, not necessarily everybody can deliver an infusion. But the actual technological step there to be able to move to an infusion-based strategy is not that great compared to some of the other interventions that we're talking about, things like ECPR. Which leads us really nicely in to the other thing, I think the second thing you mentioned Paul was ECPR. So ECPR, which we know other services, you know, such as London, setting up trials. And there are other places around the world, Paris, Australia, that are doing this already. Again, that trade-off between what's financially viable to deliver, what's practical to deliver, different geographical challenges, urban versus rural. Can we speak a little bit about ECPR? And that will probably then lead into why we're talking about medical robber and access and finances for these different therapies. For me, ECPR is the ultimate solution. And all of what we've spoke about in terms of spear is just an access to be able to potentially achieve that. If you are in a place where you can deliver ECPR exceptionally well, and the example I would also take would be the system in Minnesota, a really evolved system where they're able to take a patient into their catalab and get them onto ECPR, sometimes in as quickly as six minutes. Unbelievable timescales is just, I wish I could do that in my major trauma center, complete a primary survey and get the patient off the skewed in that timeline. So there are evolved systems that are able to deliver that. And if that's thrown on the table and accessible within your system, then I think that's what we should all be trying to aim for. There's no better evidence based intervention for refractory ZF out of hospital cardiac arrest than being able to put that patient in a rapid fashion onto ECPR in a system that can do that reproducibly, they're seeing enough volume to stay good at it. Then that would be the absolute goal standard. But the reality is that isn't available everywhere. We've mentioned about rural areas, papers, extended timescales to reach them. Then it may not be necessarily an intervention that can benefit everybody. The interesting thing with the Dutch system is that they're trying to work to a system that makes it equitable and accessible or patient to them in the Netherlands. So it'll be really interesting to see the results from that trial, probably publishing early next year from the on scene trial. So just to recap for my benefit. So we've talked about this arterial access. We've talked about monitoring through that. We've talked about ECPR and what a fantastic opportunity that is to deliver that to patients. But what we haven't talked about is the use of Roboa in medical cardiac arrest. And that will lead us on to the Erica trial, which you'll be able to give us hopefully some really interesting information about. So do you want us to talk a little bit about Roboa for medical cardiac arrests? Yeah, so I mean, even the phrase Roboa still has antibodies from some of the trauma days. So we're almost considered calling it something else. But aortic balloon occlusion, which is effectively Roboa and cardiac arrests, aims to improve coronary perfusion by increasing afterload and removing runoff. So if you're measuring it using CPR, you're trying to push a column of blood out of the heart and it has to go somewhere around the outer of the bits that we're not really interested in, whether they get perfused or not. Really, where we want the blood to go is aortic root, coronary and up to your brain. That's what we're interested in doing with recitation. And anything we can do to improve our chance of rust, the rest of the body will wait and re-perfuse itself and sort itself out. So the moment we're using drugs to increase afterload, what else could we do? Is there any animal data out there that suggests that occlusion may alter could improve coronary perfusion? Well, yes, there is. So some early models using open-chest CPR, just clamping it, seems quite dramatic at every medical cardiac arrest. They then went on to use some elegant endovascular techniques and blow a bruner when they alter. We know as Roboa, they call it a blue and occlusion back then, showed very, very striking upturns in coronary and cerebral perfusion. And as little as a few years ago, Alice Hutan's lab in Paris again shows some very nice data, showing that with aortic blue and occlusion, you get a rapid sustained increase in coronary perfusion pressure and cerebral blood flow, more rapid than you do by using adrenaline. And also, we haven't talked about as the deleterious effects of adrenaline in the cerebral circulation. So if you keep giving high doses of adrenaline, your cerebral vascular resistance goes up, your cerebral blood flow actually goes down. And maybe that's what we're seeing in some of the recitation studies, like paramedic 2, where we can get rust at the expense or cerebral outcome. So, can we use a mechanical device to do the same job as adrenaline and improve aortic dystetric blood pressure? Yes, we can. And that's where we set up our study, built on some early Norwegian data, where they demonstrated very nicely the feasibility of doing this, alongside the chaos of pre-hospital ALS, where we successfully gathered occlusion in 10 patients, and we're able to show an upturn in entitled CU2. So a surrogate marker, really, the circulatory efficacy during CPR. And we then turned that into a prospective observational study operating out of East Anglia, delivering spear, as a standard package of care, and then selecting patients into the trial, where they would use aortic balloon occlusion, so Roboa, as we know it, to the same time monitoring near infrared spectroscopy, so brain circulation, and invasive dials, so blood pressures, above the balloon tip and below the balloon tip to see, does it do the thing that it does in the research studies in animals and in labs, in humans, in the setting of adult, ongoing refractory cardic arrest? And that's the Erika trial, which is ongoing. Yeah, absolutely. So, this is a study of 40 patients in refractory cardic arrest, in the East of England area that we're able to get to, with a specially trained nodal crews deliver this, so we took a cohort of people and gave them additional training, people already delivering spear, so delivering aortic access for the hospital, we then gave them a bespoke package of additional training, and some simulation training to bring their skill levels up, to be able to safely put the device into the order, and very closely monitor the patient. Actually, doing Roboa itself could probably take you no more than a few minutes, but actually, if you want to monitor aortic zone one pressure, if you want to monitor thermal sidearm pressure, if you want to try and record central venous pressure, to make a stab at calculating coronary profusion pressure, so as John said earlier, right, A to a pressure is in there somewhere, if you don't have any sort of assessment of that, we're flying blind, but you want to do all of those things, you've got a very complex set of physiology data variables you need to collect at scene, so it takes us a little bit longer. I think it's really important, as well, to going back to that very first bit in the intro, signing around this being an access, so spear being the access to other endabascular interventions, I think it would have been much harder to undertake this study, if we didn't have a cohort of experienced spear users. And when I say that, I don't just mean predominantly the physicians that were doing the cannulation, but also our excellent critical care paramedics, something as simple as running through an arterial line that those of us that work in critical care environments will do frequently, suddenly becomes more complicated at cardiac arrest, and it becomes even more complicated when it's the triple transducer, so we can actually measure blood pressure above the balloon, below the balloon, and if there's a venous sheath also measure the central venous pressure, and making sure that the right limb of the triple transducer is connected to the right bit of kit, actually becomes quite complicated, and you're very much heads in at that point, trying to make sure that all of the right things happen in the right sequence. And I think the reason why we were able to demonstrate feasibility successfully was that we already had an extensive corporate experience of doing this in patients in at a possible cardiac arrest with the SCIRD program, so I think had we have just decided to roll out Erica from as the first intervention, I think that would have been much more tricky. I think having that experience, and also some of our ambulance crews being familiar with what we do and we turn upon seeing put drapes down from the sort of umbal icos down to the feet and create a sterile field. That's not common in most at a possible cardiac arrest, but absolutely necessary, if you go into any form of invasive endovascular intervention. And familiarity of operating around a sterile field, but those were working in in-hospital setting, working in operating theatre is second nature, but in the chaotic, unpredictable out of hospital environment, is actually quite challenging. - Yeah, well I mean, when you talk about putting drapes down and sort of getting that access in, you picture the smallest bathroom with the most difficult access that those patients always tend to arrest in and the logistics. I think logistics is so complicated out there and such an era of expertise, mainly in the in the paramedic side of practice, in pre-hospital practice, and you can see hugely how this leans upon that expertise to be able to deliver that. Just going on, I'm more aware that I keep asking about the aerocotrol a little bit too much, but in terms of where that's up to and timescales and what that may or may not tell us, can you tell us a bit about that? - Yeah, so we're about 33 patients in now, so I think over the next six months, we'll probably complete recruiting. We need to decide as an organization what Erica at East Anglia Air Ambulance looks like at the end of that. So do we believe it's a therapy? Should we continue with it for a very refined patient cohort and probably is the answer to that? Also, getting rid of it completely means you then lose your endovascular expertise that you've built up over several years or you lose a portion of it. So whilst the data gets analysed, we'll probably retain a form of it. What are our insights? Well, a lot of logistics, as John said, in terms of delivering it, but is it feasible? Yes, it is. Can an endovascular positive hem service deliver this during a cardiac arrest? Yes, they absolutely can. And we knew that from the Norwegian data set really. ALS can continue. We can concentrate on doing our access and getting a device in. Are we able to extract laboratory quality physiological data at the scene? Yes, we are. And we're able to very carefully look back through. Now there are again, whole Twitter dialogues about what AITIC does. So the pressure shows on the screen during cardiac arrest and there are very complex AI research programs involving lots of universities around the world to try and solve that problem for us. But can we deliver this to provide physiology guided resuscitation? And can we use the device to augment afterload? Yes. Can we do it in a timely fashion? Yes. I'll be able to acquire physiological data. Yes, we are. Have we analyzed all of that yet? No, we haven't. We've seen some interesting things in terms of timing. So what we can talk about is, you know, things take a long time in HEMS, don't they? Dispatch takes some time for all sorts of complicated reasons. Different HEMS services have different levels of interest in going to medical cardiac arrest. Okay, so conceptually some services sync their trauma services and are less keen to go to medical cardiac arrest because the outcomes in them to be fair are so dismal. So there are differences between services that we've needed to iron out. The timings, yeah, we often don't arrive on scene R, we're quite quick at doing our endobascular procedures, what we have learned, but actually often invasive therapies aren't happening to 45, 50 minutes from the time of the cardiac arrest. And that's the absolute Achilles heel of all of the endobascular therapies aren't they? On the plus side, I would say the aim for this is to develop something that's scalable. So ECPR, John talked to her earlier, is a complex thing to deliver, even in a very highly resource system, such as the sub 30 investigated in London with two ECMO consultants and a HEMS consultant and an advanced parlorate practitioner on a car, they struggle to get to patients in a sufficiently timely manner and to deliver orchestrate ECPR pre-hospital. This is relatively simple compared to that, it's still relies on safe ultrasound, I've got it from our access, but this is something that could be scalable. Could HEMS services across the UK deliver this if this delivers the effect we wanted to? Then absolutely. And as John alluded to, our critical care paramedic cohort are very, very good ultrasound, got it access. And in fact, in a lot of cases, they have a much more fastidious approach to some physicians who can show them what you want them to do and then basically do their own thing anyway, but that hasn't been the same in our critical care paramedic cohort, until they've much more fastidiously learnt the skills, practiced the skills, and remember to record the images during the ongoing puncture. So we can look through them and troubleshoot with them and work out how we need to change our training emphasis. So is this something that we think could be delivered by a critical care paramedic or advanced parlorate practitioner and critical care? And I think yes it is. And that I think that's where the strength in this procedure is that it's scalable and deliverable more widely than ECPR is necessarily. The availability of ECBOW in the UK is a complex field and it's geographically quite complicated as well. So your child's eye and cardiac arrest near a centre that can deliver ECPR to your Minnesota style is very, very low in the UK. And even if you are next to one, are they set up 24/7 to receive patients in refractory cardiac arrest? The vast majority, absolutely not. Is this something that could be delivered at the scene to be a bridge to risk? Or as we evolve our pre-nospital critical care and ECMO services or ECAT and a vascular cardiac arrest team services, could this be used to bridge a patient to partial roast whilst a team come and then maybe have ECMO or other services available? And I think that's probably where the strength of this lies. There'll be a lot of people listening to this. Some of whom are going to be early adopters and going to be really keen to be involved in this. Others who will want to see the evidence as it's presented. And I think both of those are really justified approaches, aren't they? But when you talk about spear and when you talk about where you've got to, it's pretty impressive how long you've been dedicated to this time wise to get to this point. And what I can imagine is that we may get to a situation where you publish something and it shows a real benefit. And then certain services, both pre-hospital and in-hospital, will then try and work out how they can get to the point of being able to deliver this package of care. And I think the fundamental that you keep referring back to is this arterial access. And even if you don't want to be involved in the whole spear package and you're not considering medical robber, knowing that the blood pressure readings that we're seeing in critically unwell patients are going to be looking much tidier in the non-invasive group. Pretty much the only reason to do that is to have a governance session where your observations are looking very nice when you're presenting the case back. It's not going to truly reflect what's going on with that patient. So there seems to be a really good case for invasive blood pressure monitoring. Can you talk a bit about the journey to get that to be a standard package of care in the right group of patients and what lessons other services can learn to get there? Absolutely. Happy to cover the journey. I think it's probably about an eight-year-long journey, but Paul and I've worked quite closely together on other projects in end-of-assular cessation. We implemented rebelling to the military. So had experience of taking end-of-assular naïve operators and training them to be able to deliver a halo procedure with robust underpinning training. So we took a lot of lessons from that and moved that into the pre-hostile environment. I started out this journey with implementing a change in ultrasound. You clearly need an ultrasound device if you're going to undertake femoral arterial access during out of hospital cardiac arrest. It's always going to be ultrasound guided. So having the right device that allows you to visualize the vessels and ideally be able to document that and say that I think is crucial. So the first few years was spent very much just implementing that change and you know, we managed to publish some guidelines and examples of how we structured that. What then followed was then the opportunity to implement the end-of-assular access options. And if you were quite cautious, we implemented that as a consultant only intervention in its infancy. That was primarily for safety and so that we could assure ourselves that we were able to undertake this new intervention in a pre-hostile environment without causing unnecessary complications because it is a high risk intervention. There is a risk of injury to the vessels, there's a risk of aneurysm, there's a risk of complications in terms of thrombosis, all of which you can only tolerate so many of those issues and then that will rapidly put a stop to your system. So we had to make sure that we were implementing it safely and robustly. And that's what sort of led to us developing the training course. The reality is common femoral arterial access in outfossil cardiac arrest is very different to trying to do this in a patient that's got an intact circulation. The images appear different, identifying the vessels, differentiating between the artery and the vein is much more challenging. And actually it was really important to actually deliver a dedicated training course specifically targeting at access during arrest rather than just relying on prior learned skill. And I suppose then the ultimate sort of secretive that was that we got challenged by one of our senior critical care paramedics. You said, look, you know the doctors are coming here often with very little experience of femoral arterial access and if they do have it it's probably not in cardiac arrest. So what's the difference between a new doctor coming into the service versus an experienced critical care paramedic who's been doing ultrasound guided radial arterial access for five, 10 years. And the reality is we didn't have an answer to that. And actually what we should do is train everybody to the same standard and you know through an evolved system. We've been able to learn the lessons from training multiple people and be able to implement what we think is a robust package for teaching common femoral access to the highest standard possible. The reality is for arterial monitoring into arrest, it probably doesn't matter that much whether you are slightly off of the midline or you're targeting the vessel at the two o'clock position. But the reason why we've been absolutely robust that you do things to the highest standard possible is that if you then want to develop any of these more invasive options such as ECPR such as Rebera you need to be able to do it properly. So that's why I've been really strict on the technique as well. That is really helpful and I think the other thing obviously from an unbelievably limited experience on my behalf it's that familiarity isn't it with setting up the transducer with the kit and how that all plays into it. And even if I guess even if we're just talking about radial artery access that again does push services along that experience curve to be able to then keep up with what may or may not evolve. I guess the one thing that people will highlight is concerns about scene time when you're talking about invasive blood pressure monitoring and there's definitely a drive isn't there within pre-hospital care and in hospital care to make sure that time that we're spending is done in the most efficient way for patient-centered outcomes. What sort of things can you share from your huge experiences about where that fits in and case selection and workflow? I think you're absolutely right sign in terms of the focus on scene time it's actually a readily available metric for us when we're analyzing cases in Hems which is probably why it's been given the focus that it has. When we consider the cohort in particular of out of hospital cardiac arrest patients without ready access to a in-hospital ECPR program there's often very little benefit to be gained by transporting patients' interest arrest. So actually the time spent trying to optimize your physiological monitoring at scene and potentially then be able to target your interventions to try to achieve rosk which in most systems you will only move once you've achieved rosk then I think there's a huge benefit. If you then look at the other patients and I'll take the Neurocritical Care Patients in example I've certainly been in situations when you've undertaken a pre-hosted emergency anesthetic using just non-invasive blood pressure monitoring and the first blood pressure that you see post-induction of anesthesia is something that's completely unbelievable. It's not uncommon to see a hugely wide and pulse pressure. It's not uncommon to see a blood pressure of 165 over 145 with a really marital pressure. And we've even got a picture in our spear slide set of an inverted non-basid blood pressure. So a blood pressure of 145 over 165. So what I'd say to teams worried about scene time is actually what does that do to your effective mental bandwidth that's seen when the non-invasive blood pressure is generating a number that you completely disregard you believe is incorrect and then into a vortex of recycling your non-invasive blood pressure multiple times to get a number that you actually feel like you can trust, believe and take action against. So for me the slight increase in scene time and actually in our data we managed to demonstrate that undertaking arterial access does prolong scene time. It's in a matter of single digit minutes. So around about five minutes prolonged. Don't forget and large number of those patients were also having pre-hospital emergency anesthesia as well and those numbers weren't just in all patients receiving emergency anesthesia. So some of the patients in the non-invasive group didn't see an anesthetic so that timeline may have been more prolonged by the anesthetic rather than the access. But what was really fascinating was that there was no difference in scene time prolongation between those that had radial arterial access and those that had femoral arterial access. So our femoral arterial access was not delaying duely. I think that was really valuable. The problem is is that you can't measure with a readily available metric what an inaccurate blood pressure does to your overall mental capacity versus an accurate continuous invasive blood pressure and the ability to accurately titrate therapy based on real-time data. So I mean clearly I'm a fan but hopefully you're sort of getting a feel of where we think maybe just focusing on scene time isn't necessarily the best available metric. And also there's something to be said about what that then results in the onward flow of that patient. So if those patients typically will always receive arterial access on arrival at hospital for example a new critical care patient that's going onwards to CT scan. Well actually if that's been done in the pre-hospital environment does that potentially speed up the flow in hospital to investigations and onward definitive intervention? The reality is we don't know because we don't scrutinize those timings in the same level of detail as what we do the pre-hospital timings because of the availability of data. So the other issue about case selection is okay we're going to select potentially viable workable as the phrase isn't it cardic arrests and we are very careful to do that as part of our initial assessment process really isn't it John to see is this somebody who could survive and if it is then game on and the other thing is you know what else you're going to do with that patient anyway the best chance of survival at this point in time in this country is to get rosket scene isn't it so if you have a hemstein deployed delivering maximum therapies to get rosket scene it has got to be the optimal way of treating that patient and what we know about you know pre-hospital therapies such as ECPRs they are very complex to deliver there isn't you know even with the so advanced parented practitioners in critical care and LES now have access to direct ECPR pathways across London but the logistics of getting someone who's in cardic arrest from their place of cardic arrest to an ECPR center in medieval design cities without massive roads and with with you know complicated congested infrastructure is really really challenging so you can have the most enthusiastic Minnesota style resuscitation teams available in the hospital but you just will not be able to get that patient out of that flat into the ambulance into the hospital through two different lifts and delivered to the lab or wherever you're going to put them in ECPR in time the old days and as an enthusiast of salvage PCI you know if you put them on mechanical CPI go to the capital I'm trying to open the coronaries you know I used to do that quite a lot I was trying to use yes to grab it trying to generate survivors in my early consultant days as it resulted in any people walking around now no it hasn't sadly so so salvage PCI so if you're if you're thinking we're not going to spend our time doing access we're going to transport this patient and where to an ECPR pathway that doesn't really exist fully in the well it doesn't exist at all outside of London really in a slick manner or are we going to deliver them to the cath lab and convince them poor intervention colleges to do salvage PCI in them well that's not going to generate a survivor either sadly so I think at this point in time therapy is we can deliver at scene the mild to my CPI and get rost probably our way we should be aiming whilst we allow the hospital services to evolve and whilst we allow advanced pre-hospital care services to develop their deliverable and advanced care therapies to try and catch up yeah and and I think that that cardiac arrest patient is is a much easier argument is the wrong word but it's a much more explicit benefit isn't it but it's those patients that are the the neuroanesthesia those ones that are critically hypotensive and and you can see the argument can't you in those cases for why scene times we do need to keep very much an eye on this and not become completely task-focused but I would guess again that's about the training that's about the system setup that's about the kit and that's about how you structure your teams in terms of how many personnel are going out there and as John has really nicely described that really excellent challenge from our paramedic colleagues about why is this only the doctor that's allowed to perform this and the movement of that forwards and the answer to all of these therapies is do more get faster get better so if you are a bit sluggish just practice more just get faster if they're meaningful things that you're delivering just be better at them do them more quickly and then and then all the argument for scene time and delay goes away doesn't it and it's also thinking about all of the work so it's not just the actual niggling of the vessel that's often the quickest part is all of the peripheral activity that goes along with it so in a system my work in now we will often that the paramedic will be setting up the kit dump for the airway whilst the doctor may be doing the arterial access but that will also include running through the transducer and connecting it to the monitor whilst the ambulance grew often and have to switch the monitoring over and it's all about just coordinating that workflow to keep things as efficient as possible we're going to pull it back in a minute to the system overall and about spare courses but before we get to that have there been any lessons learnt from spare in terms of recognition of risk yeah that's a really interesting question actually because it was an area that we probably hadn't anticipated but actually would invasive blood pressure monitoring intra-rest during chest compressions you can see the waveform actually that moment that you pause to analyse the rhythm and will still stick to ALS two minute cycles especially in PA cardiac arrest you actually have visual representation of what is happening and you remove that need for what's the people trying to feel for either central or peripheral pulses which is often highly inaccurate so rather than relying on the digitometer as some colleague described it you can actually see the pulsatile trace and if that's sufficient and a chorus one's with something that suggests there's a meaningful output then actually there isn't a requirement to restart chest compressions and the concern there is that actually in a recovering part that's just recovered from the most critical medical emergency eye it's been stopped and it's restarted to restart CPR unnecessarily just because we can't feel a pulse corresponding with sufficient pressure to be able to be felt by our hyperadrenalized fingers then actually restarting CPR and that recovering heart may be actually deleterious so instead of using that we can see the pulsatile waveform and then what then follows is you can then titrate your visit chemotherapy associated to what you're seeing in front of you and the second effect is that you then don't end up in that situation 30 seconds a minute later where people are concerned that the entire CO2 is dropped by one and now if we actually lost output can anyone feel a pulse again you can actually just see it on the screen and it's amazing how quick crews that have never experienced managing the patient with invasive arterial monitoring soon get used to seeing that visualization on the screen and focusing on those numbers. I think some of the insights we've seen from our Eric Oresco or match exactly what you said there John so in the patients who've got risk and/or survived we've seen when you look back very carefully and I think the rest is that the scene wouldn't have been aware of this because there's just too much going on but in the cold boring light of day when we look at those things in real time you can see the patients who get lost tend to either be ones who are in BTVF when we get there so they still have electrical activity or when you look carefully to the pressure traces of mechanical CPR you can see evidence of the beginnings of occasional ejection not by itself if you stock CPR enough to sustain a circulation but the heart is trying to beat and those insights we couldn't have derived unless we had invasive facial monitoring in those patients so I think it's telling us that though you know whether there's activity and as you say once we get lost we have a very very very rocky post-resuscitation phase and the reboa patients they don't just come out of VF sit up and start talking to you they are incredibly sick it's absolutely essential then to help us finesse the post-rosk phase and allow us to get the patient to hospital so early detection I think is key detection of pages you might benefit from endovascular therapies such as reboa so those pages are starting to eject his key and then as you say that very rocky post-res period and the transfer to hospital I think it greatly facilitates that I think there is an argument as well when we're looking at recognition of rosc about whether or not feeling full of pulse during chest compression uses a viable alternative and if that's all you've got available to then potentially yes just to slightly dampen the enthusiasm slightly however there is a high probability that when you're feeling through a pulse either friendly or in the carotid during compressions using your finger you may actually feed in being a spalsitility the reason we know that is that when we've cannulated and transduced both arterial and venous sheets it's not uncommon and this is the sort of second head-explored emoji moment is that it's It's not uncommon to see a DNA systolic in triple digits, so you could almost certainly be feeling the common femoral vein that's pulsatile at the moment when you stock compressions, clearly that stops being pulsatile regardless of whether there's an intact circulation or not. So, ideally, use invasive arterial blood pressure monitoring to allow you to recognise the risk if it's available to you. I think what's being clear, author-at-list discussion is that even if you aren't a believer in spear itself, there are a lot of things which come out of this in terms of benefit for other patients on there. So, we've talked about dispatch and how important that is pretty much with every time critical case and that there's an awful lot of work that all services are already doing and can continue to do because that's such an important part of the system isn't it? That is the foundation of where this all starts. We talked a lot about upskilling of individuals and of services and optimizing kits and team roles. But what we have done, I guess, is focus pretty much on the pre-hospital side of things. Does this translate into in-hospital practice? I've certainly got examples of undertaking this in the resuscitation room where I work in hospital in Stoke. It's been hugely valuable in the same way as what we found in the pre-hospital environment being able to accurately see the physiological changes being able to target our therapies and recognize the return of spontaneous circulation. So, we're fortunate we have similar types of kit. We didn't really talk about kit a huge amount before, but using catalabble level, interventional kit rather than trying to sort of use a sort of lesser type device for this high stakes intervention. If you can use the best kit possible, benefit from a cart-based ultrasound as well, so that's even better, being able to visualize the vessels, but also then just being able to share that information. And if you've got a monitoring setup, you can visually demonstrate the effectiveness of your resuscitation, I think very quickly people get on board when they can see the clear benefits in front of you, even in the in-hospital environment as well. And then there's a lot of lessons that are translating into an arrest on the ICU. I think it's managed very differently to how we probably approach things in the out-of-hospital or even the resusc environment where things are a little bit more uncontrolled, but I think that's where some of the upcoming updates to the guidelines are going to come in in terms of patients in a monitored environment, so I think specifically referring to those patients in a sort of critical care or theatre type setting. Fantastic. Well, it seems any right that we come back to spear itself. So how do you see the future of spear evolving from this point? Well, when we think about the beginnings of a spear course, it was an in-house training programme to train established East Angle and Air Ambulance Doctors and some CCP's in these techniques. And after a couple of iterations, we then started opening courses up to people who are interested in testing the water from other services, and now we're at the point where barely a week goes by, that John or I don't get a call from somebody within AUK HEMS service saying, well, either we're super keen to take this forward, how do we get a call? Or the other conversation is, well, actually we're a bit conservative on this, but we want to know, one of the conversations we need to have to drive this forward in our organisation. So, well, I'll hand over to John. John can talk about the evolution of the course beyond the initial ECSA play programme. Yeah, I think it's been really exciting. We've been fortunate to go out to a number of different air ambulances and deliver something similar to what we were doing as an internal only sort of training course, and that's been really well received. And it's great to see the enthusiasm across the UK. I think what's been really, really exciting is actually these enthusiasm wider and into Europe. We've been able to deliver two courses now in Brisbane, in Belgium with the HEMS service and a hospital over there and then later in the year, there'll be a course in Mannheim in Germany. And looking forward into 2026, that's actually interesting, South America. So we're hoping to have a trip to Brazil to deliver a spear course. And actually the course itself has evolved, as Paul said, from very much an in-house training focused predominantly on the access to actually a wider resuscitation course, and this clearly demand from people who want to push their resuscitation knowledge beyond the ALS algorithm and actually what we're finding is realistically need at least two days to deliver both the access technical skills, but also really do a deep dive into all the aspects we've discussed today. So calling in physiology, look at ECPR, well, how do you manage the crashing P patient? When you see a paracardal effusion on ultrasound, how do you differentiate that? Is it tampernard? It's an infusion. All of these sorts of things, of the course of two days we can go into in a lot more depth. And we've also had a bit of spin-off with contributing to other courses such as the Paris-Rest Geo courses, Paul mentioned that include a spear and rebelar component. So there's lots of places you can go to learn more and yeah, we're really excited about what the future holds for this system. Well, well, I really hope you enjoyed listening into that because I found that an absolutely fascinating conversation with John and Paul there. Just I mean, I don't even really know where to start so much to take away from it. It's such an inspirational group who've really taken our idea and developed it and run with it for such a long time. I love the vision and the drive to take the whole team with them towards this kind of end point that they've got in mind. Incredible. And I think, you know, what am I left with with my kind of overarching ideas and thoughts? Well, I think really what I was listening to the whole thing, it really made me just think in general about cardiac arrest care and I think it's really tempting, isn't it, to be drawn into the idea that if you follow the ALS algorithms to the T and you absolutely nail the algorithm that you're providing excellent cardiac arrest care and cardiac arrest resuscitation. But actually, I think that's probably not the case and this is a really good, in fact, excellent demonstration that we need to individualize our cardiac arrest management. And I think it also tells us that we don't really know that much despite all of the research and all of the evidence that has been gathered over the years, we still don't know heaps about the physiology of cardiac arrest and what we're doing during cardiac arrest management. I love the conversation around the fact that we're providing boluses of very strong vasopressas and ionotropes in an unmonetored patient who is critically unwell. And I just, I never thought about it like that before and it really draws you back in, it makes you think, what are we doing in cardiac arrest and what are our interventions doing to the patient? And that then made me sort of spin off more and just think about the fact that actually, isn't it fascinating that cardiac arrest care itself hasn't really advanced very much for years? I think realistically the last big change was about 20 years ago, in 2005, when we had the change from 15 to 2 to 30 to 2 and we moved away from stacked shocks to single shocks and really ever since then we've seen these sort of incremental changes and I think what I was most excited about with this concept of, of spear. And I got like thinking about it like that, it is a concept, I know they're sort of driving onwards towards the idea of rebo or an ECMO, but what they've already identified and demonstrated on their journeys, what's possible? I love the fact that we're starting to understand more about cardiac arrest like, you know, what it is, what does Rosk look like, when do we achieve Rosk and what are our interventions actually doing and how do we target physiological parameters to get the best chances of Rosk in these patients? I think there's so much more potential to come out of this group and out of spear itself, it's really exciting. I think to me, it was even more than that because it's not just about those cardiac arrest cases, it's about what we're trying to deliver with our care and with critical care and it's about taking a really strategic look at where we want to get to with what we're trying to deliver. So, you know, clearly we spoke about non-invasive versus invasive blood pressure monitoring and there's a huge amount of different parts that add in if your service, or your hospital is going to deliver that in the early phases, there's a huge amount that needs to be done in terms of staffing, equipment, training, governance and education are clearly absolutely fundamental to driving practice to where they've got it to, but I think it's a really great opportunity, isn't it, for all of us to have a think, what is it we're doing? What are we doing? What do we want to do even better and how do we get to that point? So, yeah, really inspirational, loads to think about. In the show notes, we've got a lot of papers which are referenced and hyperlinked. So, do make sure you go and check those out because I'd imagine, like us, this probably then just starts to scratch the surface of what you want to know. And also, I'd imagine quite a few people listening to this will now want to attend this beer course, we've put a link to the courses on the website, so again, go and check those out. Excellent, well that is it for roadside to recess until September, a massive thanks to John and Paul for coming on the podcast and for sharing all of their experience and their knowledge. It's been hugely valuable to us and hopefully to yourselves as well, and a massive thanks to Zull Medical Corporation for collaborating with us on the podcast and making this all free open access and available to you. So, until next time, take care of yourselves and we'll speak to you soon. Speak to you soon.